Exterior wall building codes speaks to What are exterior wall building codes and why exterior wall building codes.
The major impact of building codes on the design of the exterior wall in the areas of structural strength, fire resistance and energy efficiency.
Strength requirements relate to the strength and stiffness of the wall system itself and to the adequacy of its attachments to the building frame, with specific reference to wind and seismic loading.
Fire requirements are concerned with the combustibility of the wall materials, the fire resistance ratings and vertical dimensions of parapets and spandrels, the fire resistance ratings of exterior walls facing other buildings that are near enough to raise questions of fire spread from one building and another and the closing off of walls. This is known as firestopping of any vertical passages in the wall that are more than one story in height.
At each floor the space inside the column covers and the space between the exterior wall system and the edges of floors must be firestopped using a steel plate and grout, metal lathe and plaster, mineral wool safing or other material that can restrict the passage of smoke and fire through these gaps.
Energy conservation requirements are becoming more and more demanding. Most energy codes allow several alternate approaches to demonstrating compliance. In the prescriptive approach minimum thermal resistances of panels, spandrels and glass, vapour retarder performance and maximum levels of air leakage are specified.
For example in the International Energy Conservation Code prescriptive approach for commercial buildings, up to 40 percent of the above grade walls may be glazed, with a minimum factor ranging from 1.20 to 0.35 (6.8 to 2.0 W/sq meter-0K) depending on the climate zone in which the building is located.
Component trade off and systems analysis approaches give the building designer more flexibility in selecting enclosure systems while demonstrating that the overall energy performance of the proposed design is equal or superior to that of the same building constructed to meet the prescriptive code requirements.